An electric wire conductor is excellent in space saving and flexibility and is less likely to concentrate a load on specific elemental wires, and a covered electric wire and a wire harness contain the electric wire conductor. The electric wire conductor contains a wire strand containing a plurality of elemental wires twisted together. The wire strand has a sector-shaped part in which a cross-section intersecting an axial direction of the wire strand contains either a single edge or two edges touching each other at an apex, and an outward curve connecting the ends of the single edge or the two edges. In the sector-shaped part, the elemental wires having deformation ratios from a circle lower at an outer peripheral part facing an outer periphery of the sector-shaped part than at a center part of the sector-shaped part located inside the outer peripheral part in the cross-section intersecting the axial direction.